/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package org.apache.metron.stellar.common.utils;

import java.util.HashMap;
import java.util.regex.Pattern;

public enum PatternCache {
  INSTANCE;

  private static final ThreadLocal<HashMap<String,Pattern>> _cache = ThreadLocal.withInitial(() ->
          new HashMap<>());

  public Pattern getPattern(String patternString){
    Pattern pattern = _cache.get().get(patternString);
    if(pattern == null){
      pattern = Pattern.compile(patternString);
      _cache.get().put(patternString,pattern);
    }
    return pattern;
  }
}
